Piston drill guide block



July 30, 1940. R. M. ULRICH PIsToN DRILL GUIDE BLOCK Filed Dec. 21, 19582 Sheets-Sheet ll fig. 8.

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@will July 3o, 1940. R M, um@ 2,209,433

PIsToN DRILL GUIDE BLocx Filed nec. 21, 1938 2 sheets-sheet 2 PatentedJuly 30, 1940 PIsToN DRILL GUIDE BLOCK Raymond M. Ulrich, Shelbyville,Ill., assgnor to AloisW.` Graf, Strasburg, Ill.

Application December 21, 1938, Serial No. 247,088

'7 claims. (ol. 77-62) My invention relates to piston drillguide blocks,and more particularlyto piston expander drill guide blocks whichcooperate with the slot of the expansible piston slnrt.

This application is a continuation-in-part of my copending applicationSerial No. 204,272, iled April 26, 1938, entitled.y Piston. expandersand method of installation. y

Heretofore, numerous piston expanders and expansible pistons have beenproposed. Such devices, however, have often been characterized by acomplex structure which necessitated special machining of the piston andspecial tools for the installation of such devices. It, of course, wouldbe desirable to provide a simple piston expander suitable for pistons ofVarious sizes and of different thicknesses of piston walls which wouldserve to produce an expansionxnt within the piston cylinder without theuse of special afl--` justable devices. 1

It is, therefore, an object ofiny invention to provide an improvedpiston expander and method of installation which will overcome many ofthe disadvantages inherent in the devices of the prior art and whichwill be simple and reliable in operation. r

A further object of my invention is to provide an improved piston drillguide block and method of preparation of expansible pistons for thereception of a piston expander cooperating with the piston block of theexpansible skirt.

` It is a'still further object of my invention to provide an improvedpiston drill guideblo'ck and method of preparation of expansible pistonsfor the reception of a piston expander'which will produce the samedegree of expansion fit within the piston cylinder in the'case ofthick-Walled pistons, as is the case in thin-walled pistons.

A still further object of my invention is to provide a new and improveddrill guide block for producing indentaticns in the faces o f the slotof a piston which have surfaces which are oblique sections of acylindrical surface. n

4 The novel features which I believe to be characteristic of myinvention are set forth with particularity in the appended claims. Myinvention itself, however, both as to its organization and method ofoperation, together with further objects and advantages thereof,v willbe understood better by reference tothe following description taken inconnection with theaccompanying drawings in which Figs. 1 and 2 show oneembodiment of my piston expander; Figs. 3 and 4 show alternativeembodiments 'of my piston expander; Fig. 5 showsanexterior view of apiston skirt provided with my expander; Fig.

i 6 shows a perspective view of my piston drill guide block; Fig. 7shows theapplication of my drill guide block to the skirt of a piston;Figs. 8 and 9 explain the operation of the drill guide block inconnection with thin Walled pistons; Figs. 10 `and 11 explain theoperationof the drill guide vblock in connection with thick-Walled pis-vtons; Fig. 12 shows a perspectivefview of another type of lpistonexpander; Fig. 13 shows a perspective View of another type of pistondrill guide block; Fig. 14 shows the application ofthis modified formvof drill guide block to the slot of a piston skirt; Fig. l5 explainsthe operation of the drill guide block in connection withthin-walledpistons; Fig. 16 explains the operation of the drill guideblock in connection with thin-walled pistons; Fig. 17 shows the expanderof Fig. 12 inserted in a piston.

Referring to Figs. 1 and 2 of the drawings, I have illustrated thereinone embodiment of myI piston expandercomprising an arcuate` shaped bodymember I preferably of spring steel, provided with a plurality ofprojections or lugs` 2 in the proximity of the ends of the body land a2f" projection or lugy 3 at an intermediate portion thereof. Theprojectio-ns 2 near the ends of the body l are set back from theextremities thereof so as to leave flat portions 4, the purpose of whichwill subsequently become apparent. The projecting members 2 and 3 arearranged substantially perpendicular to the plane of the arc of the bodyof the expander, but preferably at slight angles to the perpendicular ofthe plane so Ythat the curved outer portions of the projections 2 and 3form slight angles to the right and left of a line perpendicular to theplane of the arc of the body member l..

In Fig. 3 there is shown a modification of my piston expander which ismade of thinner material and the projections thereof have convex 40bearing surfaces and concave inner surfaces. In this figure thoseportions of the expander corresponding to Figs. 1 and 2 have been giventhe same reference characters together with the subscript a. In Fig. 4 astill further modifica# tion of my invention is shown in which partsycorresponding to the expander shown in Figs. 1 and 2 have been givensimilar reference characters, together with the subscript b. In thisinstance, however, the member Ib is arcuate in one direction through thegreater portion` of its` length and near the extremities thereof the'member lh is bent over in the reverse directionv in a U shape. Thus, inthis embodiment the? i. cylindrical surface. y 5 which is normallyprovided with a slot 6 havfiat portions of the expander corresponding to4 in the Figures 1 and 2 and to 4a in Figure 3 are now displaced topoints on the opposite side of the projections 2b as indicated by theflat surfaces 4b in the figure. If desired, the curvature of the bodymember Ib may be such that the projections 2b and 3b are in the samerelative positions as the projections 2 and 3 of Fig. 1. Each of theprojections in these two figures are also placed at slight angles to theperpendicular to the piane of the 'curvature of the body members Ia andIb. While the expanders shown in Figs. 1 to 4 have been illustrated aseach having three projections, it will of course beA apparent to thoseskilled in the art that a greater or lesser number of projections Imaybe utilized since it is only necessary to have the concave bearingsurfaces of the projections at acute angles to a plane perpendicular tothe plane of the body members, or at acute angles to a planeperpendicular to a plane which is tangent to the curvatureof the pistonvskirt at the slo-t. The projections-'at these angles are arranged so asto cooperate and be complementary to indentations inthe faces of theslot of the piston skirt.

Fig. 5 discloses a piston having an expansible skirt provided with aslot therein. The faces of the slot have indentations therein which havesurfaces corresponding to oblique sections of a The expansible pistonskirt ing indentations 'I on the faces thereof is shown with anAexpander of the type disclosed in Figs. land 2 arranged-Within thepiston skirt 5 and ,having projections 2 and 3 extending into theindentations l. .The flat end portions 4 of the body member I of theexpander serve as bearing surfaces adjacent the inside wall of thepiston skirt thereby preventingla possible change in the position orshape of the expander, due to temperature variations which would tend tocause the end projections 2 to extend to the Wall of the piston anundesired amount. The fiat portions 4 vand the body member I aretherefore contiguous to the inside wall of the piston skirt.

yIt of course will. be apparent that expanders of the type shown inFigs. 3 and .4 can likewise be utilized in a manner similar to thatshown in Fig. 5.. vDue to simplicity of the expander it will foundthat-the expander is adaptable to all types of. piston, regardless of theinside shape of the piston, with reference to strengthening struts andribs. v

vReference may now be had to Fig. 6 in whichI have showna piston drillguide block comprising anelongated body portiton Il having a concaveface!) the radius of curvature of which correspends approximately to theradius of curvature ofthe pistons more commonlyin use. This concavesurfaces is provided with a pair of projec- "f'tions I Il and II locatedadjacent opposite ends of the elongated bodyportion 8 so as to engagethe slotB ofthe piston skirt 5 shown. in Fig. 5. At vone extremitysuitable fastening means are provided comprising a head member I2, aflat por- `Al-tion I3, a threaded portion I4 and a nut I5 which "thefaces Yof the Spiston slot. The body portion 8 serves to maintain theblock 8 in proper operative position on the piston skirt. The headmember I2-.bears against the inside surface -of the piston skirt while,the flat` portion I3` is locatedbetween forming an acute angle with theperpendicular to the tangent of the curvature of the concave face 9 atthe center line extending between the projections I and I I. Thealternate axes of the members I6, I'I and I8 are so placed to the rightand left of the center line that the drill bit cooperating within theguides will produce indentations in the faces of the slot which aresections of a cylindrical surface each dened. by planes which areoblique angled with respect to the axis of said surface. Fig. 7 showsthe drill guide block 8 in operative relation with respect to the pistonskirt 5 and from this view it is apparent that the axes of the drill bitguides I6 and I8 are in the same plane which is at an acute angle to theright of a plane perpendicular to a plane tangent to the curvature ofthe piston skirt at theV slot, whereas the axis of the drill bit guideII is in a plane which is at an acute angle to the left of the planeperpendicular to a plane tangent to the curvature of the piston skirt 5at the slot.

From Figs. 8 and 9, which are respectively sectional vieWs along thelines A--B and C-D of Fig. 7, it will be seen that ina thin-walledpiston skirt the inside View of the arcuate indentations in the faces ofthe slot would present indentations in staggered relation so that iftangents to the indentations were drawn on the inside of the skirtparallel to the facesl of the piston slot 6, they are spaced apart anappreciable amount. Thus, in a thin-walled piston skirt expanders of thetype shown in Figs. l, 2 and 3 do not exert as great a tension on thepiston skirt as would be the case in thick-walled piston skirts. Figs.10- and 1l are sectional views respectively along the lines A-B and C--Dof Fig. '7 in the instance where thick-walled pistons are utilized. Inthis instance itwill be apparent from the gures that when viewed fromthe inside of the piston skirt the arcuate indentations will appear tobe more nearly in line and hence if tangents to the indentations aredrawn parallel to the piston slotl on the inside of the piston skirt,these tangents will be closer together than wasv the case in athin-walled piston. y Thus an expander such as shown in Figs. l, 2 `and3, when inserted in the indentations thus made will exert a greaterforce on a thick-walled piston than on a thin-walled piston. The anglesat which the drill bit guides I6, Il and I8 have been arranged are sochosen that any expander of the type shown in Figs. 1, 2, 3 and 4 willalways produce the proper biasing effect against the slo-t faces at theindentations to produce the proper expansion fit of a piston within thepiston cylinder. From this it is apparent that the single type of pistonexpander produces the proper expansion in both thin- Walled .andthick-walled piston skirts. Thus no compensation or adjustment isrequired on the part of the person installing these expanders to providefor the variation in the thickness of piston walls.

While for the purpose of illustration the drill bit guide blocks shownin Figs. 6 to Il have been shown of the type having three guidestherein, it of course Willv be apparent to those skilled in the art thata greater or lesser number of guides may beV utilized in accordance withthe number of projections on the type of expander to be installed. Thiswill be apparent to those skilled in the art when it is remembered thatthe guides each are at a slight angle to a plane perpendicular to aplane tangent to the curvature ofthe Elfil piston skirt at the slotv ortangentlto the" curvature of the drill guide block. This is illustratedin Fig. 12v ofthe drawingswherein I have-shown another embodimentof apiston expander comprising a body member I9 arranged in a double reversecurve shape or, inv

the flat portions 2| serve as inside bearing sur-v faces on the innerface of the piston skirt.. If, at the center of the convex'.` surfacesof the projections 22 planes are drawn tangent thereto .lt will be foundthat the planes ofthe two projections 22 will form an acute angle thevertex of which will be on the inside of the piston. The

projections 22, therefore, may be said to be at acute angles to eachother and at acute angles to a plane perpendicular. to the plane of thebody I9 of the expander.y

In Fig. 13 I have shown a piston drill guide block having a body portion23 which has a concave shape 24, the radius of curvature of whichcorresponds approximately to the radius of curvature of the pistons morecommonly in use. At the upper end of the concave surface 24 there n isprovided a projection 25for the purpose of engaging the slot of thepiston skirt.

At the other extremity of the body23 suitable fastening means areprovidedcomprising a head member 23, a flat portion 21, a threadedportion 2B and a nut 29 which serves to maintain the block 23 in properoperative relation on the piston skirt. The head member 26 bears againstthe inside surface of the piston skirt while the flat portion 21 islocated between the faces of the slot. The body portion 23 isfurthermore provided with a plurality of drill bit guides and 3|,respectively, which are spaced apart and extend from the concave surface24 through the block 23, the

axis of each guide forming an acute angle with the perpendicular to thetangent of the curvature of the concave face 24 at the center lineextending between the projection 25 and the aperture for the fasteningmeans 26 to 29. The axes of the guides 30 and 3l are so placed to theright and left of the center line that the drill bits cooperating withinthe guides will produce indentations in the faces of the slot which areoblique sections of a cylindrical surface.

In Fig. 14 I have shown a portion 32 of the piston skirt, a piston skirtslot 33 and another portion of a piston skirt 34. The drill guide block23 is shown in opposite relation with respect to the piston slot 33.will be apparent that the axes of the drill bit guides 30 and 3| have acommon plane which is substantially at right angles to the piston slot33. If planes along the axes of the drill bit guides 30 and 3l areformed which are perpendicular to the common plane it will be found thatthese planes form an acute angle somewhere to the inside of the pistonskirt.

Fig. 15 shows a sectional view along the line E-F of Fig. 14 in theinstance where a thinwalled piston skirt is used. From this View it willbecome apparent that the arcuate indentations in the faces of the slotwhen viewed from From this view it spaced apart an appreciable amount'.Thus in a thin-walled piston .skirt the expanders of the type shownin'Fig. 12 will not exert as great a tension on:V the skirt. as would'bethe case in thick-walled.

piston skirts. I l f Fig. 16 .shows a sectional View along` the line E-Fof Fig. 14'in-y the instance wherey thick-.- walled pistons-areutilized."` In this instance it will be apparent from the figureA thatwhen viewed from thefinside of the piston skirt .the arcuateindentations Willappearto be, closer.1to. gether .and hence if anAexpander such as shown the inside :ofthe: piston .fskirtpare spaced-apart an lappreciable amount v If tangentsA to the indentations`Weredrawn'on the inside ofgthexskirt parallel toI theV faces 4of theslot 33 they wouldbe;

in Fig. 12, is inserted Yin the indentations, it will exert agreaterlforce on a thick-walled piston than fonv ay thin-walled piston. Theangles at which 4the dri11bit guides 30and 3l have4 been arrangedhavebeenso chosen that anyexpander` o f theitypeshownin Fig. 12 will alwaysproduce the proper biasing effectzagainst the slot facesv of ;theindentations to vproduce the proper ex. pansion fit ofthe piston vWithinthe piston lcyle inder.v y

Fig. 17 illustrates ,the manner in which an expander of the type shownin Fig. 12 is insertedl in the indentationsiwhich are formed in bothofthe faces'of the piston slot 33 by the drill bits cooperating in theguides 30 and 3l. 'It will be seen that the convex surfaces of` theexpander projections22 are complementary to the arcuate indentations 35which have concave surfaceseach comprising oblique sections of acylindrical surface. l 1

While-I have shown and described my invention in connection with certainspecific embodiments, it will, of course be understood that I do notwish to be limited thereto, since it is apparent that modifications maybe made in the instrumentalities employed Without departing from thespirit and scope of my invention as set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A drill guide block for cooperation with a slotted piston skirtcomprising a block having a concave surface provided with projectingmeans 1 thereon for engaging the slot of said piston skirt,

block having a concave face adjacent said pis` ton skirt, means on saidconcave face for engaging said piston slot, there being a plurality ofdrill bit guides extending from said concave face through said block,the axis of each guide forming an acute angle with the perpendicular tothe tangent of the curvature of said piston skirt at said slot, the axesof said guides being to the right and left of the center line of saidslot whereby the drill bit cooperating within said guide will produceindentations in the faces of said slot so that tangents thereto parallelto said slot face on the inside of said skirt are closer together inthick-walled pistons than in thin-walled pistons.

`3. A drill guide block for cooperation with a concave surface adjacentlto the outer curved surface of said piston skirt, meansprovided on isoblique angled relative to the face of said slot.

4. A drill guide block for cooperation with a piston skirt having a slottherein, said drill bit guide block having a plurality of drill bitguides arranged to have their axes in two planes, said planes being atacute angles to the right and to the left of a plane perpendicular tothe tangent of the curvature of said piston skirt at said slot wherebydrill bits cooperating with said guide will produce indentations in thefaces of said slot which haveA surfaces comprising sections of acylindrical surface formed by planes which are oblique angled relativeto the axis of said surface.

5. A drill guide block for cooperation with the slot of an expansiblepiston skirt comprising a block having a concave face adjacent saidpiston skirt, means on said concave face for engaging said piston slot,there being two drill bit guides extending from said concave facethrough said block, the axes of said guides being in a planeperpendicular to said piston block, the axes of said guides forming. anacute angle the vertex slotted piston skirt comprising a block having aof which is to the interior of said piston skirt whereby drill bitscooperating within said guide will produce in the faces of said pistonslot indentations each of which comprise sections of a cylindricalsurface formed by planes which are Y oblique angled relative to the axisof said surface.

6. A drill guidev block for cooperation with the slot of an expansiblepiston skirt comprising a block having a. concave face adjacent saidpiston skirt, means on said concave face for engaging said piston slotand. for maintaining said block in operative position, there being twodrill bit guides extending from said concave face through said block,the axes of said guides being in a plane perpendicular to said pistonslot and forming an acute angle the vertex of which is to the interiorof said piston. skirt whereby drill bits cooperating within said guidewill produce an in dentation in each of the faces of said slot so thatthe indentations when viewed from the inside of said skirt are closertogether in thick- Walled pistons than in the thin-walled pistons.

7. A drill guide block for cooperation with a slotted piston skirtcomprising a block having a concave: surface adjacent to the outervcurved surface of said piston skirt, there being a plurality of spacedapart drill bit guides the axes of which are arranged at acute angles tothe right and to the left of a plane perpendicular to the tangent of thecurvature of the said piston skirt at said slot whereby drill bitscooperating Within said guide will produce spaced apart indentations inkthe faces of said slot which have surfaces comprising sections of acylindrical surface formed by planes which are oblique angled relativeto the axis of said surface.

RAYMOND M. ULRICH.

